1. Field of the Invention
The present invention relates to a liquid-cooled transformer assembly for microwave ovens, a method for manufacturing the same, and a microwave oven equipped with the same.
2. Description of the Related Art
A conventional transformer for microwave ovens increases a voltage of a power source, and includes a core and primary and secondary windings wound around the core. The transformer is installed in an electrical components area, partitioned from a cooking chamber, together with other electrical components such as a high-voltage capacitor and a cooling fan. The transformer inherently generates heat by resistance of the coils and generation of eddy current due to variation of magnetic flux density of the cores. The heat is removed by a cooling device having a fan and a fan motor in an air-cooling manner.
Because the transformer generates vibration and noise during its operation, the transformer is provided with a separate rubber cushion to overcome the above problems.
Furthermore, because the cooling procedure for the transformer, which involves only air cooling, has a low cooling efficiency, an operational efficiency of the transformer is decreased. Consequently, the components, such as the core and the coils, must be manufactured with large surface areas to compensate for the decrease of operational efficiency, thereby increasing production costs. In addition, because vibration-absorbing elements such as the rubber cushions are required to absorb the vibration and noise, the production cost is further increased.
To prevent noise, rise of temperature, and corrosion of the core, the conventional transformer is immersed in a varnish solution to form a thin film on outer surfaces of the transformer during the manufacturing process, thereby increasing production cost and manufacturing time. Furthermore, because insulating material is required to prevent electric leakage from the transformer mounted on a microwave oven, labor costs are increased.